In any electrical contact, the actual co-operating contacting surfaces are not perfectly smooth or continuously planar. Indeed, such contact surfaces, if magnified sufficiently, may have the general appearance of a lunar landscape or even that of a mountain range. In other words, the contact surfaces, themselves, may be very rough, having a number of irregular peaks and a number of irregular pits or valleys. Except as discussed hereafter with particular reference to the present invention, the actual electrical transmission--i.e., the transmission of electrical current from one contact surface to the other--therefore ordinarily occurs only at those places where there is real physical contact between the material of the one co-operating contact surface and the material of the other co-operating contact surface.
Such co-operating electrical contact surfaces, in general, where the contact stabilization material of the present invention is particularly useful, are very broadly categorized; and may be those that used in circumstances where relatively high current transfers between the contacting surfaces--relatively high being several milliamperes up to several amperes or more--and even more particularly such as those that are used in micropower installations where extremely low currents are expected to pass between the co-operating electrical contact surfaces.
For example, high current applications may include plug-in communications and standby power applications such as may be used by ground surface personnel when working with and communicating to personnel on board commercial jet aircraft and the like. Low power and micropower applications include low level video, radio frequency, audio frequency and computer circuitry, and connections therefore.
In any electrical contact situation, between co-operating contact surfaces, there may be surface resistance due to oxidized metal or other foreign materials; and if there is any varnish present, there may be sufficiently higher resistance that virtual insulation between the contacting surfacs may occur under certain conditions.
For example, in high current applications, there may be heating deformation due to resistance of the materials of the contacting surfaces, or due to the presence of surface resistance material, such that there is a possibility of a chemical reaction that may take place due to the heat. Moreover, if there is a further material present, such as previous materials that have been attempted to be used for the same purposes as the material of the present invention (as discussed below), there may be a chemical reaction between the contact metal and a trapped gas film that may have developed due to the heat, and either the gas film or the chemical reaction may further cause anomalous behaviour of the near-contact boundry in the contact region.
In such micropower current applications as low current or power level video cable connectors, radio frequency or audio frequency connectors, or cable connectors between computer components or the computer and its peripheral components, there may be occasions when there is not a sufficient signal power available to ensure that there is a reliable maintenance of signal flow. Where the signals involved are alternating complex waveform signals, such as audio or video signals from a cartridge, reading head or laser head, the current flow may be momentarily interrupted at zero-crossing conditions--that is, where the voltage potential between the contact surfaces changes from a directed positive to a directed negative potential, or vice versa--and in those circumstances it is possible that the current flow may only be re-established after there has been sufficient voltage rise to break down the potential gap between the co-operating electrical contact surfaces, or of the material between the surfaces.
In radio frequency circuitry, this discontinuous behavior at zero-crossing may lead to line reflections that may add artifacts to the signal. For example, with video signals, the zero-crossing discontinuity that may occur between otherwise co-operating electrical contact surfaces may show up as video ghosts or as imperfect chroma demodulation, due to apparent noise.
In computer cicuitry, zero-crossing or other contact-induced signal or data artifacts may appear as increased noise, and in certain circumstances there may be rectification artifacts--particularly in binary data flow conditions--where program crashes, incorrect data transmission, or spurious parity or cyclic redundancy error conditions may occur.
A prior attempt to provide contact stabilization materials in the electrical industry, particularly in respect of micropower audio frequency applications as well radio frequency and computer data transmission applications, has been to use octadecyl alcohol-doped palm oil, or similar materials. However, in any vulcanizable vegetable oil, such as palm oil or otherwise, there is a propensity for the oils to cross-link during their use, particularly in the presence of metallic materials that could act as catalyst. This cross linking amounts to the creation of a varnish, by which a virtual insulative property then occurs. Thus, using such materials as octadecyl alcohol-doped palm oil, even though initial results were encouraging, they then proved to be of no value if not of negative value due to the varnishing and consequent contact insulating characteristies that developed.
A material that can exhibit both low resistance and high resistance, and which may be electrically activated so as to be switched from one of those resistance states to the other, is particularly referred to in U.S. Pat. No. 4,359,414, issued Nov. 16, 1982 in the name of Mastrangelo et al.
Other materials that are known for conditioning electrical contacts include a very specifically taught and involved polyether co-polymer referred to in Cuddy et al, U. S. Pat. No. 4,360,144, issued Nov. 23, 1982. That patent teaches the use of a liquid co-polymer whose sole purpose is to inhibit the production of dross during wave soldering procedures. The polyether co-polymer floats on top of the hot liquid solder both, and it must comprise an heteric or block co-polymer of a dihydroxyphenol together with at least one lower alkylene oxide, with at least 20% by weight of oxyethylene groups, and having a molecular weight in the range of 500 to 3000 but preferably 1000 to 3000. As noted above, the sole and only purpose of that material, specifically stated in the patent, is to inhibit dross by floating on the surface of liquid solder during wave soldering procedures.
A solid electrolyte which is formed of cross-linked elastomeric complex material charged with one or more ionizable salts of high ionic conduction is taught in Andre et al, U.S. Pat. No. 4,357,401, issued Nov. 2, 1982. The particular purpose, however, for that macromolecular material of ionic conduction is so as to permit its use as a solid electrolyte in such circumstances as electrochemical generators or potentiometric measurement cells--particularly those that are intended for use at high temperatures.
Non-ionic related difunctional block polymers which terminate in primary hydroxyl groups with molecular weights ranging from 1000 to over 15,000, are defined in Condensed Chemical Dictionary, Van Nostrand Reinhold, 1971, in association with the trade mark PLURONIC.TM.. These non-ionic block polymers are polyoxyalkylene derivatives of propylene glycol; they are available in liquid, paste, flake, powder or cast-solid forms, and are used as defoaming agents, emulsifying and demulsifying agents, binders, stabilizers, dispersing agents, wetting agents, rinse aids, and chemical intermediates.